Hydrocarbon fluids, such as oil and natural gas, are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various well completion components may be installed to control and enhance the efficiency of producing the various fluids from the reservoir. In some oilfields, the fluid produced from the well may include a high concentration (e.g., up to 10%) of sour gas (e.g., hydrogen sulfide). This sour gas, together with the majority of the lighter fractions of the produced hydrocarbon fluids, may be re-injected into the reservoir either as a means of disposal or to enhance production of the base hydrocarbon fluid. However, injection cycling can cause changes in the composition of the hydrocarbon fluid being produced through the wellbore. These fluid composition characteristics may be measured during well intervention procedures during which production is temporarily stopped and appropriate sensors can then be deployed in the wellbore. In sour fields, however, the presence of the sour gas can either impede or altogether prevent the opportunity to perform these types of measurements during an intervention operation.